ABCA4 p.Lys969Ala
| Predicted by SNAP2: | A: D (71%), C: D (71%), D: D (75%), E: D (71%), F: D (75%), G: D (75%), H: D (66%), I: D (66%), L: D (71%), M: D (95%), N: D (63%), P: D (75%), Q: D (63%), R: N (53%), S: D (66%), T: D (63%), V: D (71%), W: D (85%), Y: D (71%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Interaction of the nucleotide binding domains and ... Biochemistry. 2006 Mar 21;45(11):3813-23. Biswas-Fiss EE
Interaction of the nucleotide binding domains and regulation of the ATPase activity of the human retina specific ABC transporter, ABCR.
Biochemistry. 2006 Mar 21;45(11):3813-23., [PMID:16533065]
Abstract [show]
We report here a novel regulation of the ATPase activity of the human retina specific ATP binding cassette transporter (ABC), ABCR, by nucleotide binding domain interactions. We also present evidence that recombinant nucleotide binding domains of ABCR interact in vitro in the complete absence of transmembrane domains (TMDs). Although similar domain-domain interactions have been described in other ABC transporters, the roles of such interactions on the enzymatic mechanisms of these transporters have not been demonstrated experimentally. A quantitative analysis of the in vitro interactions as a function of the nucleotide-bound state demonstrated that the interaction takes place in the absence of nucleotide as well as in the presence of ATP and that it only attenuates in the ADP-bound state. Analysis of the ATPase activities of these proteins in free and complex states indicated that the NBD1-NBD2 interaction significantly influences the ATPase activity. Further investigation, using site-specific mutants, showed that mutations in NBD2 but not NBD1 led to the alteration of the ATPase activity of the NBD1.NBD2 complex and residue Arg 2038 is critical to this regulation. These data indicate that changes in the oligomeric state of the nucleotide binding domains of ABCR are coupled to ATP hydrolysis and might represent a possible signal for the TMDs of ABCR to export the bound substrate. Furthermore, the data support a mechanistic model in which, upon binding of NBD2, NBD1 binds ATP but does not hydrolyze it or does so with a significantly reduced rate.
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No. Sentence Comment
74 The following complementary oligonucleotides were used as mutagenic primers to generate the mutant NBD1 and NBD2 proteins: NBD1Pro940Arg (5'-GGT AAA GAT TTT TGA GCG CTG TGG CCG GCC AGC TG-3'), NBD1 Walker A, K969A, T970A (5'-CAA TGG AGC TGG GGC AGC CAC CAC CTT GTC CAT CC-3'), NBD2 Walker A, K1978A, T1979A (5'-GAA TGG TGC CGG CGC AGC AAC CAC ATT CAA GAT GC-3'), and NBD2 R2038W (5'-CTT TAC CTT TAT GCC AGG CTT CGA GGT GTA CCA GC-3').
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ABCA4 p.Lys969Ala 16533065:74:208
status: NEW199 The affinity of interaction decreased under all conditions examined, as determined by comparison of the Kd values (Table Table 2: Modulation of ATPase Activities of NBD1‚NBD2 Complexes by Site-Specific Mutations NBD1‚NBD2 mutation domain NBD1‚NBD2 ATPasea (pmol/min) NBD1‚NBD2 ATPaseexptl (pmol/min) NBD1‚NBD2 ATPasecalcd b (pmol/min) motif/disease NBD1mut‚NBD2wt K969A, T970A NBD1 1.9 ( 0.4/5.3 ( 0.1 5.1 ( 0.1 7.2 synthetic NBD1wt‚NBD2mut K1978A, 1979A NBD2 3.1 ( 0.2/1.6 ( 0.3 1.5 ( 0.2 4.7 synthetic NBD1mut‚NBD2wt P940R NBD1 1.9 ( 0.3/5.2 ( 0.2 4.3 ( 0.1 7.1 AMD NBD1wt‚NBD2mut R2038W NBD2 3.1 ( 0.1/2.0 ( 0.2 4.4 ( 0.2 5.1 STGD NBD1wt‚NBD2wt wild type N/A 3.0 ( 0.3/5.4 ( 0.1 5.30 ( 0.3 8.4 none a Experimental ATPase activity corresponding to 6 pmol of the individual domains, NBD1 and NBD2, respectively.
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ABCA4 p.Lys969Ala 16533065:199:406
status: NEW